Typical power amplifier systems known in the art include output inductors in series with the output stage and cause output inductor distortion as well as output impedance (referred to as DCR or DC Resistance). As a consequence of this output impedance causing added distortion and a reduced damping-factor (the ability to control the moving mass of the loudspeaker drivers of a loudspeaker system) the audio signal will suffer.
Class-D amplifier Integrated Circuit's (IC's) have relative high resistor values inside integrated-circuit packages. This is because of a limitation of the silicon material and its inability to handle the thermal effect of having high currents passed through internal resistors with low ohmic values. Furthermore, general distortion (referred as Total harmonic distortion) is evident in Class-D amplifier IC's as well as Class-D amplifiers and is, in general, caused by the Class-D amplifiers switching nature. In other words switching output-stages adds distortion that modulates down into the audio band.